Thermal mapping gives information about thermal loading within a body. Examples are heat distribution inside a microchip, and the location of energetically active structures of a living organism, such as a cell. Heretofore, thermal mapping or imaging has been realized for macro-objects using thermo-vision cameras, i.e., devices which convert thermal emission into visible radiation. However, the thermal emission wavelength utilized by these cameras is around 7-13 μm, and thus the technology cannot be applied to the study of micro-objects, which have sizes that are close to the wavelength of thermal emission. For such applications, other technology is required.
Current imaging methods, including thermal imaging, are limited by their ability to resolve dynamic processes which occur on time scales faster than approximately 0.1 seconds. Laser scanning microscopy is extensively used in bio-imaging due to the high resolution provided by this technique. In many applications, imaging is done with, for example, two different laser excitations to calculate the ratio of two chromophore populations in living cells. Typically this is achieved by switching the laser beam after each frame of data acquisition using raster scanning of the laser beam. However, in the case of fast dynamical processes under investigation, such a strategy is often insufficient, as by the time the second laser begins to acquire an image (typically 100s of milliseconds) the dynamical picture has changed, giving erroneous signals.